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Re: BUG: [preempt-rt] scheduling while atomic: stapio


Josh Stone wrote:
On 05/20/2009 02:44 AM, Kiran wrote:
BUG: scheduling while atomic: stapio/0x00000001/26142, CPU#3
[...]
 [<ffffffff812a2dea>] cpufreq_unregister_notifier+0x35/0x5c
 [<ffffffffa02e0a1f>] _stp_kill_time+0xb6/0xbd [stap_246f93f30a500769142af9987624737a_5072]
 [<ffffffffa02e1749>] probe_1391+0x3c/0xa8 [stap_246f93f30a500769142af9987624737a_5072]
 [<ffffffffa02e2621>] enter_end_probe+0x14a/0x1e3 [stap_246f93f30a500769142af9987624737a_5072]

enter_end_probe will call preempt_disable, and apparently the call path from cpufreq_unregister_notifier can sleep. Is this true only of the RT kernel?

The call into the __synchronize_sched() from synchronize_rcu() appears to be able to sleep regardless of -rt. It's possible -rt is more likely to make them sleep.



-- Darren Hart IBM Linux Technology Center Real-Time Linux Team


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